Only show Apply All button if more than one change is selected

Release-Notes: skip
Google-bug-id: b/234578022
Change-Id: Ic0ebb06ba7d9096d268cf65355addc415af8acd8
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-hashtag-flow/gr-change-list-hashtag-flow.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-hashtag-flow/gr-change-list-hashtag-flow.ts
index 18cfe61..dbc06d2 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-hashtag-flow/gr-change-list-hashtag-flow.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-hashtag-flow/gr-change-list-hashtag-flow.ts
@@ -176,8 +176,8 @@
             flatten
             ?disabled=${applyToAllDisabled}
             @click=${this.applyHashtagToAll}
-            >Apply to all</gr-button
-          >
+            >Apply${this.selectedChanges.length > 1 ? ' to all' : nothing}
+          </gr-button>
           <gr-button
             id="remove-hashtags-button"
             flatten
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-topic-flow/gr-change-list-topic-flow.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-topic-flow/gr-change-list-topic-flow.ts
index deca7a6..0aaf6fc 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-topic-flow/gr-change-list-topic-flow.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-topic-flow/gr-change-list-topic-flow.ts
@@ -175,7 +175,9 @@
             flatten
             ?disabled=${this.selectedExistingTopics.size !== 1}
             @click=${this.applyTopicToAll}
-            >Apply to all</gr-button
+            >Apply${this.selectedChanges.length > 1
+              ? ' to all'
+              : nothing}</gr-button
           >
           <gr-button
             id="remove-topics-button"